So you couldn't train around that? If you're reaching failure in roughly 15 seconds or less you're going to be hitting your fast twitch fibers. With the eccentric causing more damage than the contraction, wouldn't bands actually be ideal for burning out the last of the muscle fibers if you want to get technical? By the resistance decreasing on the way back it'll allow for more TUT and a few extra cheat reps than normal.
Like I said, scientifically speaking and not pulling uneducated broscience out of my ass, it can be done. It's not as efficient as easily adjustable weights and machines, but just because they're bands doesn't mean you can't put the necessary stress on the muscle in order to induce hypertrophy.
I can talk science with you to, so the band is not a constant tension the whole way up and down. Yes hitting the phosphocreatine system and glycolotic system would allow for type 2 a fibers to be hit.
you can use bands to help muscle mass as a type of drop set incorporating the size principle, ending an exercise, after dumbells or weight training. Hitting those big type 2 muscle fibers. Which is basically the same thing as a drop set.
Lets take the bicep curl. The eccentric portion of the exercise is the best for muscle building, which is with any exercise.
But with bands you are losing so much tension during half of the eccentric portion of the exercise. Which is strongest portion of the muscle action.
Talking about the bands resistance at the full bottom of the movement is basically 0, while the top of the portion is full resistance.
But since the top of the movement in the bicep curl is weakest point, and tge bands resistance is the most strongest, its not going to hit the big type 2 fibers as effectively.
The actual strongest part of the bicep curl is half way between the top and bottom, I believe this has to do with the distance between the moment arm and the pivot of the bicep and the tendon. Causing this point of where the muscle force of contraction is the strongest.
Yet bands dont give adequate resistance at this point compared to the top of the movement.
this is why dumbells are effective, because the tension on the muscle is heavy where the muscle needs the most force to contract.
edit- this is way to much typing on an iphone to explain whats needed. Lets just agree to disagree. Lol